This invention relates to a subscriber call simulator for use in testing a telephone switching system.
In prior art, a telephone switching system only carries out a connecting service which connects a subscriber's telephone set of an originator with another subscriber's telephone set of a receiver which the originator dials. Such a connecting service is called a basic service. In order to test the basic service of the telephone switching system, use is made of a subscriber call simulator which makes the telephone switching system repeatedly carry out the basic service. In other words, the subscriber call simulator repeatedly carries out a basic operation which comprises call, dial number transmission, answer, speech confirmation, and disconnection, in the manner which will later be described in more detail. The subscriber call simulator is connected through subscriber lines to the telephone switching system. The subscriber call simulator acts as pseudo-subscriber's telephone sets. At any rate, a conventional subscriber call simulator only carries out the basic operation.
With an appearance of an electronic switching system of a stored program control type, it has become possible to provide various new services, such as a call forwarding service, a three-way calling service, and so on in addition to the basic service. The conventional subscriber call simulator is disadvantageous in that it is impossible to carry out the test of the such new services. As a result, the subscriber's telephone sets must be directly put into operation on manually carrying out each new service by one who tests the new service. Inasmuch as each of those tests is a manual test, it takes a long time and a lot of man-hours to test the new services. On simultaneously carrying out the new services, the subscriber lines must be used without overlap. When the conventional subscriber call simulator is connected to another telephone switching system, reset must be made as regards all information indicative of, for example, dial numbers. Such a manual test is not efficient and can not shorten a test time interval.